Improvement in metal screws and nuts



A@sind ditta.

HENRY cQr'nA-Rson,

OF NEW YORK, N.y Y.

Letters Patent No. 113,557, dated April y1.1, 1.871.

IIVIFROVEMEN-'l IN METALSYCREWS AND NUTS.

The Schedule referred to in these Letters Patent and. making pax-t ofthe same.

To all whom it may conce/rn:

Be it known that I, HENRY G. PEARsoN, of the city, county, and State ofNew York, have invented certain Improvements in Metal-Screws, vand Nutsfor the same and I do hereby declare that'theV following, taken inconnection with the drawing which accompanies and forms part of this specitication,jis a description of my invention sucient to' enable thoseskilled in the art to practice it.-

My invention consists in a novel formation of the thread of a screw orbolt to enable it the better to hold its position when subjected to jarsand jolts, without turning in the nut or other objectin Vwhich itis-inserted; in a corresponding formation of the .threads vof anni'.applicableI to be used with such a screw or bolt; and in combining withsuch a nut aconvex steel washer, as hereinafter set forth. I make myscrew with a series of indentations or grooves, either on one or bothsides of its thread, at

It will be seen that this construction admits of readily screwing thescrew to place, lbut oiiers a iirxu and positive resistance againstitsgetting accidentally lloosened by being turned backward.

,Figurel illustratesra uut constructed as a countervpart of the screw orbolt, having its thread notched on one face or sidecorrespondingly withtig. 3

O nlyone form of` `notch is shown, but the thread may'have itsl seriesofnotches or indeutations of any appropriate configuration 'adapted tothat of the holt 0l'. screw., Y

Figure 5 is a central section, and Figure 6, a plan oi'a concave metalwasher, preferably ot' steel, designed to be used iu some cases inconnection with my improved unt, and placed between the nut and theobject held hy the screw and uut.

` VIts object is to secure a still tighter hold by tending, whencompressed, to force the swells or elevations ofthe thread ot' the screwinto the correspouding,r depressions or cavities on the thread of theuut, and (vice versa.

Y Instead of such a washer an India-rubber or other elastic washermaybeV used.

Figure 7 lshows in section,.and Figure 8 in plan, one of my improvednotch-threaded nuts, with one of these metallic concave washers looselyaffixed thereto. I connect them as follows:

On that side of the nut which is to bear against the object held orfastened, a shallowv depression, a little deeper than the thickness ofthe washer, is made, circular, square, or otherwise, asthe case may be,to con form to the form of lthe washer, and slightly grooved to receiveits edge. The washer is then inserted therein, its convex faceprojecting beyond the face of lthe nut, as seen in the gure; and tosecure it to place a few blows or indentations at theedge of thedepression will expand the metal at such points suiciently to overlapthe washer andV keep it in its place; orl

punch-holes may be` struck aroundin several places. It must lie looselyenough in its seat to permit its edge, when 'the washer is temporarilydattened by screwing the nut vagainst a surface, to spread at its edges,and also when released to resume its normal position.

In some cases I slit or cut the washers from either their inner or outeredge nearly through to the other edge, iuorder to render them moreelastic. One of these convex washers may, if desired, be lodged in,-

each face of the nut.

My invention is applicable in 4almost every branch of the artsrwherebolts and nuts or male and vfemalescrews are used. It will be foundespecially valuable in all cases where there is much motion and jarringof the machinery, and a consequent tendency vto a loosening of theparts; as, for instance, in axle nuts, to prevent the wheels of vehiclesfrom running oii; in water-faucets', the screws of which should be heldpermanently to prevent leakage; in connecting the valveplate to thevalve-stem in a steam-engine; in securing ish-plates toconnect the endsof railway-rails, 860.]

I claim- 1. 'A bolt or screw having a series of indentations on one orboth sides ofthe thread, substantially as de scribed, in such mannerthat the indentations will act as a series of detents, for the purposeset forth.

2. A nut havinga series ofindentations on its thread, substantially asdescribed, and adapted'for use in connection with a bolt or screwindented Vas described.

3. Such aunt, when usedinconnection with a loose convex steel-washer, oritseqnivalent, as described.

' HENRY G. IEARSON.

Witnesses:

JOHN J. HALsTnD, W. BRADFORD.

